Recent and future declines of a historically widespread pollinator linked to climate,land cover,and pesticides

The acute decline in global biodiversity includes not only the loss of rare species, but also the rapid collapse of common species across many different taxa. The loss of pollinating insects is of particular concern because of the ecological and economic values these species provide. The western bumble bee (Bombus occidentalis) was once common in western North America, but this species has become increasingly rare through much of its range. To understand potential mechanisms driving these declines, we used Bayesian occupancy models to investigate the effects of climate and land cover from 1998 to 2020, pesticide use from 2008 to 2014, and projected expected occupancy under three future scenarios. Using 14,457 surveys across 2.8 million km² in the western United States, we found strong negative relationships between increasing temperature and drought on occupancy and identified neonicotinoids as the pesticides of greatest negative influence across our study region. The mean predicted occupancy declined by 57% from 1998 to 2020, ranging from 15 to 83% declines across 16 ecoregions. Even under the most optimistic scenario, we found continued declines in nearly half of the ecoregions by the 2050s and mean declines of 93% under the most severe scenario across all ecoregions. This assessment underscores the tenuous future of B. occidentalis and demonstrates the scale of stressors likely contributing to rapid loss of related pollinator species throughout the globe. Scaled-up, international species-monitoring schemes and improved integration of data from formal surveys and community science will substantively improve the understanding of stressors and bumble bee population trends.

There are many examples of the loss of an iconic species where the culprit was unmistakable and the outcome was clear, but the reasons why common species decline is often not obvious and likely due to multiple causes. During the 19th century, shotgun blasts across central North America signaled the demise of the passenger pigeon (Ectopistes migratorius), once estimated to be 40% of the total bird population in the continent with up to 2 billion individuals (1). Over a century later, we have libraries of laws, policies, and best practices guiding conservation efforts, yet we find ourselves amid a new period of mass extinction (2, 3). Today, species’ declines often stem from indirect effects of human activities such as climate change or environmental degradation via gradual land conversion. Increasingly, common but understudied species are quietly disappearing over short time periods. The global decline of insect pollinators is an example of such a pattern (3–5).By facilitating reproduction in over 85% of flowering plants (6), pollinators provide a critical ecosystem function, create the foundation of terrestrial food webs, and serve as a linchpin to cascading effects across species (7). Many forbs have coevolved mutualistic relationships with pollinators, with forbs providing nectar or pollen and pollinators increasing forb fecundity (seed set) by orders of magnitude (8). Forbs in turn provide a food resource for other taxa, including species of conservation need and economic interest. For example, greater sage-grouse (Centrocercus urophasianus) depends on early spring forbs during brooding (9) and brown bear’s (Ursus arctos) seasonal diets can consist largely of flower roots such as sweet vetch (Hedysarum spp.) (10). Pollinators also support food webs by serving as food for insectivorous birds and lizards and other arthropods such as dragonflies, ants, and spiders (11). Losing even a single common pollinator species can disrupt the entire pollinator networks (7, 12), with abrupt consequences for the species that directly or indirectly rely on them for food, including humans which benefit from crop pollination services of $1.5 billion annually in the United States alone (13). Because of the integral role of pollinators across ecosystems, especially related to species of concern and human benefit, it is imperative to evaluate the drivers of pollinator declines.Drastic declines in pollinators are well represented by the story of the western bumble bee (Bombus occidentalis) which was once broadly distributed and locally abundant throughout western North America (14). The historical distribution of B. occidentalis extended from alpine regions of Arizona and New Mexico to central British Columbia and from the Pacific coastline east to the Black Hills of South Dakota (14, 15). As demand for greenhouse pollination grew in the 1990s, industrial scale rearing and commercialization of B. occidentalis grew as well due to the species’ biological and economic attributes (16). Starting in 1996, captive reared B. occidentalis populations distributed across North America to greenhouses and open field settings for pollination services experienced increased disease, particularly the fungus Vairimorpha (previously Nosema) bombi (17), providing a likely source of disease to wild colonies. Captive rearing became unsustainable due to disease impacts on managed colonies and was abandoned by the commercial bumble bee industry in the early 2000s (18). The demise of commercial B. occidentalis populations coincided with declines observed in wild B. occidentalis starting in 1998 in southern Oregon (19), urban San Francisco (20), and British Columbia (21). An independent assessment of V. bombi in museum specimens demonstrated increased prevalence of the pathogen in wild B. occidentalis starting in 1994 (22), supporting the hypothesis that the continental spread of V. bombi via the commercial pollination industry contributed to the wild B. occidentalis decline into the early 2000s (5).In 2015, the U.S. Fish and Wildlife Service (FWS) was petitioned to list B. occidentalis as threatened or endangered under the Endangered Species Act (23). Studies attributed declines of B. occidentalis populations to V. bombi, but also to additional factors including other diseases, habitat destruction, lethal and sublethal effects of pesticides, climate change, competition with nonnative honey bees (Apis mellifera), and high vulnerability of the species to negative genetic factors arising from reductions in population size due to haplodiploid reproduction (24, 25). Most information regarding the impacts of these threats has been drawn from localized studies and studies of surrogate bumble bee species. No studies have quantitatively investigated the cumulative effects of changing climate, land cover, and pesticide use. Therefore, the effect of each of these stressors, independently or concurrently, on B. occidentalis at range-wide scales remains unclear, subsequently leaving best management directions equally uncertain.Disentangling the relative contribution of potential drivers to range-wide trends necessitates an extensive investigation using methods that can integrate diverse data sources across the multidecadal time span of declines. Prior research has investigated the relationships between bumble bee species declines and a variety of stressors (24, 25). However, studies of Bombus species rarely evaluate multiple types of stressors simultaneously to allow for a more direct comparison of mechanisms of decline while also employing analytical methods that account for the imperfect detection of species during surveys. Failure to account for imperfect detection results in the confounding of the occupancy and detection processes and the degree of bias introduced is unknowable (26). Hierarchical models provide a less biased approach by separating the observation process involving sampling error from the biological processes of interest.Here, we build on previous research and apply robust quantitative methods that account for imperfect detection to test competing mechanisms associated with the decline of this once-widespread North American pollinator. We use hierarchical Bayesian occupancy models to investigate the contributions of climate, land cover, and pesticide use to trends in B. occidentalis occupancy across the western conterminous United States. We investigate the effects of climate and land cover on B. occidentalis occupancy from 1998 to 2020 and incorporate the effects of pesticides in a subset analysis from 2008 to 2014. We evaluate trends in occupancy across the range of B. occidentalis and among ecoregions representing unique geographic areas where populations experience varying intensities of stressors (Fig. 1A). In addition to estimating contemporary, spatially explicit trends using preexisting and newly collected bumble bee survey data, we also use a scenario approach to project future occupancy to the mid-century (2050 to 2059). Our unique approach to project future declines blends multiple climate models, emission levels, land cover change forecasts, and potential effects from other continued stressors to generate three future scenarios encompassing a range of plausible outcomes.Open in a separate windowFig. 1.Maps of ecoregions used to assess changes in the occupancy of B. occidentalis (A), mean predicted occupancy in 1998 and 2020 (B, C), and projected mean occupancy under three future scenarios (D, E, F) in the western conterminous United States.     

Case report 751

We present an unusual case of spindle cell lipoma of the foot which produced marked bone erosion. Spindle cell lipoma was initially described in the mid-1970s as having the characteristics of a lipoma with partial or total replacement of mature fat by collagen-forming spindle cells. This lesion is most commonly found in the subcutaneous tissue of the posterior neck and shoulder in men between 45 and 65 years of age.     

Soft tissue metastasis of a chemodectoma: a case report and review of the literature.

A case of a single soft tissue metastases (abdominal wall) occurring 15 years after removal of chemodectoma of the right carotid bifurcation is described. The tumor had apparently been completely removed with excision of portions of the common, external and internal carotid arteries up to the base of the skull. Seven years later osteolytic and osteoblastic lesions were noted in the cervical and thoracic vertebrae which were radiated with 3500 rad. The 19 previously reported cases of chemodectomas with distant metastases are reviewed.     

Microcatheter Tip Enhancement in Fluoroscopy: A Comparison of Techniques

We compared three techniques for enhancement of microcatheter tips in fluoroscopic images: conventional subtraction technique (CST); averaged image subtraction technique (AIST), which we have developed; and double average filtering (DAF) technique, which uses nonlinear background estimates. A pulsed fluoroscopic image sequence was obtained as a microcatheter was passed through a carotid phantom that was on top of a head phantom. The carotid phantom was a silicone cylinder containing a simulated vessel with the shape and curvatures of the internal carotid artery. The three techniques were applied to the images of the sequence, then the catheter tip was manually identified in each image, and 100 x 100 pixel images, centered at the indicated microcatheter tip positions, were extracted for the evaluations. The signal-to-noise ratio (SNR) was calculated in each of the extracted images from which the mean value of the SNR and its standard deviation (SD) were calculated for each technique. The mean values and the standard deviations were 4.36 (SD 3.40) for CST, 6.34 (SD 3.62) for AIST, and 3.55 (SD 1.27) for DAF. AIST had a higher SNR compared to CST in almost all frames. Although DAF yielded the smallest mean SNR value, it yielded the best SNR in those frames in which the microcatheter tip did not move between frames. We conclude that AIST provides the best SNR for a moving microcatheter tip and that DAF is optimal for a temporarily stationary microcatheter tip.     

Roles of the immune system in skin cancer

Over the past several decades, there has been increasing interest in understanding the roles of the immune system in the development and progression of cancer. The importance of the immune system in human skin cancer has been long recognized based primarily upon the increased incidence of skin cancers in organ transplant recipients and mechanisms of ultraviolet (UV) radiation-mediated immunomodulation. In this review, we integrate multiple lines of evidence highlighting the roles of the immune system in skin cancer. First, we discuss the concepts of cancer immunosurveillance and immunoediting as they might relate to human skin cancers. We then describe the clinical and molecular mechanisms of skin cancer development and progression in the contexts of therapeutic immunosuppression in organ transplant recipients, viral oncogenesis, and UV radiation-induced immunomodulation with a primary focus on basal cell carcinoma and squamous cell carcinoma. The clinical evidence supporting expanding roles for immunotherapy is also described. Finally, we discuss recent research examining the functions of particular immune cell subsets in skin cancer and how they might contribute to both antitumour and protumour effects. A better understanding of the biological mechanisms of cancer immunosurveillance holds the promise of enabling better therapies.     

Completely self-contained cell culture system: from storage to use

In vitro cell culture systems provide researchers the appropriate tools for effectively studying cell growth and differentiation, understanding cellular response to specific environmental stimuli, and elucidating the function of heterologous biological molecules produced from expression systems. All in vitro cell culture systems require a specific culture media formulated to the nutritional and metabolic requirements of the particular cell type to be cultured. However, the complexity of these systems varies depending on the model organism origin of the cells being cultured (e.g., bacteria, plants, yeast or animal). Unlike bacteria and yeast, mammalian cell cultures require sophisticated auxiliary technologies (e.g., controlled gas mixtures and pressure flow systems, specialized facilities and equipment) and careful handling by trained personnel. These complex requirements pose a limitation to transferring cells to and from remote field locations for investigations. Furthermore, this limitation is a technical hurdle in the development of technologies involving use of live cells (e.g., cytosensors). We identified a novel and unrealized feature in the conventional cell culture system that may be exploited to adapt simple existing technologies to form a portable apparatus for storing and growing cells. The approach we describe is a completely self-contained cell culture system that not only will bring down the cost of culturing cells but also will expand cell culture applications in medicine, research, environmental health, and safety.     

Treatment of human polyomavirus‐7‐associated rash and pruritus with topical cidofovir in a lung transplant patient: Case report and literature review

Human polyomavirus‐7‐associated rash and pruritus (PVARP) is a chronic superficial viral skin infection, which primarily impacts immunocompromised individuals. We report on a case of PVARP in a lung transplant recipient. Our patient developed symptoms 13 years after being on his immunosuppressive regimen, with an insidious course of progressive gray lichenification with marked islands of sparing and quality of life‐altering pruritus. Treatment for PVARP is not established; however, topical cidofovir combined with immunomodulation may offer sustained therapeutic benefit.     

Activation of peroxisome proliferator-activated receptor isoforms and inhibition of prostaglandin H(2) synthases by ibuprofen, naproxen, and indomethacin.

A series of nonsteroidal anti-inflammatory drugs (NSAIDs) [S(+)-naproxen, ibuprofen isomers, and indomethacin] were evaluated for their activation of peroxisome proliferator-activated receptor (PPAR) alpha and gamma isoforms in CV-1 cells co-transfected with rat PPAR alpha and gamma, and peroxisome proliferator response element (PPRE)-luciferase reporter gene plasmids, for stimulation of peroxisomal fatty acyl CoA beta-oxidase activity in H4IIEC3 cells, and for comparative inhibition of ovine prostaglandin endoperoxide H synthase (PGHS)-1 and PGHS-2 and arachidonic acid-induced human platelet activation. Each drug produced a concentration-dependent activation of the PPAR isoforms and fatty acid beta-oxidase activity, inhibition of human arachidonic acid-induced platelet aggregation and serotonin secretion, and inhibition of PGHS-1 and PGHS-2 activities. For PPARalpha activation in CV-1 and H4IIEC3 cells, and the stimulation of fatty acyl oxidase activity in H4IIEC3 cells, the rank order of stereoselectivity was S(+)- ibuprofen > R(-)-ibuprofen; S(+)-ibuprofen was more potent than indomethacin and naproxen on these parameters. On PPARgamma, the rank order was S(+)-naproxen > indomethacin > S(+)-ibuprofen > R(-)-ibuprofen. Each drug inhibited PGHS-1 activity and platelet aggregation with the same rank order of indomethacin > S(+)-ibuprofen > S(+)-naproxen > R(-)-ibuprofen. Notably, the S(+)-isomer of ibuprofen was 32-, 41-, and 96-fold more potent than the R(-)-isomer for the inhibition of PGHS-1 activity, human platelet aggregation, and serotonin secretion, respectively. On PGHS-2, the ibuprofen isomers showed no selectivity, and indomethacin, S(+)-ibuprofen, and S(+)-naproxen were 6-, 27-, and 5-fold more potent as inhibitors of PGHS-1 than PGHS-2 activity. These results demonstrate that the mechanisms of action of NSAIDs on these cell systems are different, and we propose that the pharmacological effects of NSAIDs may be related to both their profile of inhibition of PGHS enzymes and the activation of PPARalpha and/or PPARgamma isoforms.     

Keratome,a Better Alternative Scalpel to No. 15 Blade for Finer Incision—Randomized Control Trial

Background  Scalpel is the most common and oldest instrument used by surgeons for incision and to perform the surgery. A lot of improvement has occurred in the design of scalpel from the flint knife to the modern Bard-Parker handle with blades. The quest for improvement and finding a better instrument is neverending. In this study, we present an alternative scalpel to the no. 15 blade most commonly used by plastic surgeons. Material and Methods  Consultants and residents in plastic surgery department used a no.15 blade and a 15-degree straight keratome on randomly selected patients and used subjective numerical rating scale to assess the ease of incision and dissection. The data were collected and statistically analyzed. Results  In this study, 89 patients were included out of which 68 cases were operated by the consultants and 21 cases were operated by residents. The average score of ease of incision using a no. 15 blade by the consultants was 6.52 and by the residents was 6.125. The average score of ease of incision using a 15-degree straight keratome by the consultants was 8.74 and by the residents was 8.84. p -Value was statistically significant when no. 15 blades and 15-degree straight keratome were compared. Conclusion  15-degree straight keratome is an excellent scalpel that can be used in preference to no. 15 blade as it is difficult to use.     

Alopecia: a review of laser and light therapies

Since the 1980s, laser technology has become increasingly popular to treat a variety of cutaneous conditions. Its successful use as an epilator comes with the rare but interesting side effect of paradoxical hypertrichosis. In this review, we summarize cases describing hair growth after photoepilation, as well as studies testing laser and light sources as treatment for alopecia, particularly androgenetic alopecia and alopecia areata. We also discuss the possible biologic mechanisms by which phototherapy induces hair regeneration.